Abstract Imanis is a reporter gene imaging company which has chosen to emphasize NIS technology over other reporter proteins. NIS is the sodium iodide symporter, which mediates the uptake and concentration of iodide in the thyroid gland, providing the basis for diagnostic thyroid radioimaging and radioiodine therapy. NIS reporter gene technology allows accurate, sensitive, high-resolution visualization of NIS-modified cells, genes and viruses in living mammals (mouse to human). Additionally, NIS lacks immunogenicity (NIS is a self-protein) and is harmless to targeted tissues, allowing for longitudinal imaging throughout the lifespan of the animal. NIS-expressing cells and tissues can be imaged with a variety of readily available anionic radiotracers such as 125I, 124I, 125I, B18F4 (tetraflouoroborate) and 99mTcO4 (pertechnetate) NIS-expressing cells can also be destroyed using beta- or alpha- particle emitting anions (131I, 188ReO4/perrhenate, or 211Astatide). The overarching goal of this SBIR application is to generate NIS variants that can be used to enhance the sensitivity of NIS reporter gene imaging to monitor virus, gene and cell therapies. During Phase I part of the award, we screened a large number of NIS mutations. We have subsequently identified and generated NIS mutants that demonstrated superior isotope uptake and met the agreed milestone of the Phase I grant. In this Phase II application, we will build on those findings and will develop, validate and market the next generation of NIS reporter genes tailored specifically for optimal performance with 99mTcO4 and B18F4 radiotracers. These NIS variants will be commercially developed to provide the scientific and medical community with vastly improved in vivo reporter gene imaging solutions.